I picked up my new to me 01 today. I noticed warm or cold after the truck sits for 5 mins or so when you first fire it up it knocks about 2-3 times. The VP and injectors were replaced 60k miles ago. Guy changed it himself and didn't sound to confident on setting it up. Can a VP be out of time ?

Secondly i noticed it was wet around a few of the injectors. I'm wondering if the pressure bleeds off enough and this is causing the knock ?

I didn't notice any white smoke on start up and it fires instant without waiting for the grid heaters.

Truck is bone stock and a 6 speed. Pump and injectors are rebuilt stock. Got a receipt the guy paid $1000 for stock injectors and a $600 core charge:O

So I put 60 miles on it today. I dunno if its just me now, but it sounds like the knock is always present but nowhere near as pronounced as when it first fires up. If you accelerate fairly quick while its building boost you don't hear it. Let off and you hear it more in the 1000-1300rpm range on deceleration. Or if you slowly ease into it. Seemed like it was more noticeable on the 1st start up of the day.

If it sits for say 5 minutes when it fires up you will hear 3-4 knocks then it lets up.

Sure sounds like its coming from the top end. Checked the dipstick and no smell of diesel in the crankcase. Only smoke from the tailpipe was when i brought it up to 2000rpm in 3rd and then floored it going up a hill. blew out a little cloud. It was raining and dark outside today, but it wasn't coal black smoke. Never hesitates or misfires.

Oil pressure seems fine.

Can a fire knock only be caused by an injector or can the pump cause this too ?

Well you never want diesel comin out of your lines, if it's wet at the block double check it's all six lines are tight, it's a 3/4 or 19mm, if it's tight the o ring may be junk and need to be replaced, my .02, also try turning up your radio and just driving it a bit and try to pay no attention to any noises, I swear the sec you think you hear one odd rattle you start hearing over listening and your hear stuff that isn't even there lol

2002 QCSB that compound and down, loaded up and truckin! To view links or images in signatures your post count must be 3 or greater. You currently have 0 posts.

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I talked to the owner today and he said it had the knock before the pump/injectors were changed. Been running like this for 60k miles has not gotten better/worse. The dodge dealership told him it was in the computer programming.....??

The truck was accidented back in 07 and wrote off. (rollover according to the history check)

Now this has got me wondering if its a wrist pin/rod ect that originated from the roll over.

I hear ya on thinking you hear things when you try hard, but this definately has a distict knock when you first start it. If you shut it off and immediatly start it back up no knock.

There is some oil from the blowbye tube on the front of the engine. Didn't see any smoke comming out the tube. I noticed some oil around the oil fill cap, but i have taken the cap off while its running and it won't flutter the cap and don't feel any big amounts of air comming out. The guy said he changed the cover gasket on the side of the block. I read in another thread a guy with a scored #6 blew out that seal.

If it was from the lower end should it not get louder with rpm/load ? And why so pronounced on start up lacking oil somewhere ?

Fired up my 12v and not even remotley close noise from it.

I got some lucas injector cleaner, and no i didn't run any snake oil in the fuel tank. I have not put the lucas stuff in. I'll try some 2 cycle oil to see if it helps.

No-one said anything about the valves or more specifically the clearances.In my experience a top end knock is usually either a leaking injector nozzle or a bad or damaged valve.If it is a top end problem the easiest way to track it down is loosen off one high pressure injector line at a time and listen for the knock to stop.That at least will tell you where to start the diagnosis.

I'm going to borrow a temp gun and see what that reads at the exhaust manifold/head on a cold start up. Seller said he adjusted the valves. He was actually a marine mechanic and seemed fairly knowledgeable on the cummins motors.
Seems odd though that it had the knock apparently before the new Vp and injectors. You would have thought a new VP/complete injector and lift pump would have cured it if it was fuel. Says the dealership said it was casused by the compter programming...... never heard that one before.

Is the ecm programming different from a SO to HO engine ? Say it had a SO pump on a HO engine would there be any timing issues with stock programming ?

Ok i drove it to work today and when i got home i opened the hood and noticed the injector on the front cylinder is the only one that was moist. The more i listened to it the more it sounds like its the front cylinder. I listened underneath back by the flywheel and by the front tire. Noise really sounds more like from the top.

So i cracked the front injector open. It quieted down the motor some. (Mind you at full temp you don't really hear but a faint knock) BUT when i tightened the injector back up there was about 3 distinct knocks then went away. Tried this a few times and everytime the injector starts to tighten up 3-4 knocks. Like a high pitched tink tink tink. Tried a couple other injectors and none of them did this.

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